Safety switch mechanism



June 8 1926.

J. R. KELLEY SAFETY SWITCH MECHANISM 2 Sheets-iSheet 1 Filed June 2, 1921 at uuq June 8 1926. I 1,588,377

J. R. KELLEY SAFETY WITCH MECHANISM I Filed June 2. 1921 2 Sheets-Sheet 2 8 ""T 7 C\ H a v d n E 5 I I i 5 f i Jj E /N s ll f w 2 L q a 1 6 K 2 NF n \all Patented June 8, 1926.

UNITED STATES JOHN R. KELLEY, F COVINGTON, KENTUCKY.

SAFETY SWITCH MECHANISM.

Application filed June 2,

An object of my invention is to provide a. switch mechanism adapted to preclude initial overloading of a motor.

Another object is to provide a switch mechanism. for the purpose stated adapted to preclude closing of the circuit embracing the motor unless the motor has been conditioned for the running current to be sup plied thereto.

Another object is to provide a switch mechanism for the purposes stated that will auton'iatically lock the mechanism against closing of the circuit unless the switch mechanisms are in their proper or normal relation before starting the motor.

Another object is to provide a device for the mirposes stated that is simple in operation and construction and that is practically fool proof.

These and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which Fig. l is a fragmental side elevation of a frame having mounted upon it a switch I'i'lQCllfilllSlll embodying'my invention.

F 2 is an end elevation of some of the parts shown in Fig. 1.

Fig. 3 is an enlarged sectional view on line 3--3 of Fig. 1.

a is an enlarged perspective view of a spring latch forming a detail of my in vention.

Fig. 5 is a diagrammatic view of the wiring of the switch and the motor and showing a modified construction of the parts shown in Fig. 3.

My invention comprises a control switch A shunted. across the line wires Z) and 5 adapted to be locked against the closing of the circuit embracing itself and the operating switch D when the operating switch is in any position other than that which it should assume when a motor M is to be first energized or started.

I; The control switch A comprises a housing mounted upon the frame C and containing a sleeve a of some non-magnetic material, such as brass, about which is disposed an electric winding (4 adapted with the magnetic core a disposed within the sleeve a to form an electro-magnet. The core 0, has a central bore (1 thru which extends a reciprocating rod (4 having mounted upon it an armature a adapted to be attracted by the core a when energized. A non-magnetic collar 1 is mounted upon the rod 0.

1921. Serial No. 474,464.

adjacent one end thereof, which end extends thru the frame C and has mounted upon it a suitable handle or knob a whereby the rod a may be longitudinally reciprocated in the sleeve. A suitable key a may be employed to preclude rotatory motion of the rod A block a upon which the housing lS mounted, spaces the forward end of the housing from the rear of the frame 0. A metallic ring a of magnetically responsive material spaces the rear end of the sleeve from the rear end of the housing. A block a mounted on the housing and thru which the rod a extends, has mounted upon it a metallic band a having aconica-l face. The metallic band is electrically connected with the operating switch in a manner which will be more fully explained hereafter. The rear end of the rod a, or in other words the end spaced from the knob a has mounted upon it a block a of insulating material upon which is mounted the spring contact arms an adapted to make an electrical connect-ion with the conical face of the metallic band a. Normally the arms a do not engage the metallic band, and when the arms are moved into contact with said band, the arms are tensioned so that when the force that held the arms in contact upon the ring has been withdrawn, the tendency of the spring arms to assume their normally unstrained positions causes the rod (6 to be moved longitudinally in such direction that the arms a are disengaged from the metallic band a. The spring contact arms are electrically connected with a conductor post a mounted upon the block (1 adjacent the housing a by means of a flexible conductor a. The core a and the armature a bear such relation that when the electro-magnet is energized, the contact arms a will move into engagement with the metallic band a and the armature a will assume a position in immediate proximity to the core and will be retained in such position by the magnetic attraction of the core against the yielding resistance of the spring arms a. The winding (1 of the electro-magnet is electrically connected with the metallic band a and with the return wire 6.

A source of electrical supply B, represented as a battery, has one of its poles connected with feed line wire I) and its other pole connected with return line wire I). The line wire I) is electrically connected with the conductor post a, The current passing ill throua n the line wire I) and through the control switch A passes to the operating switch l) by way of the wire 5 lhe operating switch I) is mounted upon an insulating bracket 0 formed on the frame C. The wire 6 is electrically connected with contact (Z mounted upon the bracket 0 and the return wire 6 is electrically connected with a contact 55 mounted upon the bracket 0 adjacent the contact (Z. A CODCJIC- tor bar (Z is pivotally mounted upon the -contact (Z and a conductor bar d is pivotally mounted upon the contact cl, the conductor bars being attached to an insulating connector rod (Z Each conductor bar comprises a starting arm (Z and a running arm J. The starting arms of the bars d and d are disposed upon the same side of the connector 6Z and have mounted upon them the contact buttons al adapted to be moved into engagement with the starting contact buttons (Z mounted upon the springs d" connected with the opposite termina s of a motor M. Suitable resistances E are interposed between the contacts (i and the motor terminals. The running arms (Z of the bars are adapted to be moved into engagement with the running contacts 03 connected with opposite terminals of the motor M. The contacts (Z and cl are disposed intermediate the starting contacts d and running contacts (Z in such relation that when the motorhas been started by means of passing the current tl'irough the starting arms and the starting contacts, and then the con ductor bars are actuated about their pivotal mountings so as to break the circuit through the starting contacts (Z and (Z and to reestablish circuit through the running arms (5 and running contacts a, the current will follow the same path through the motor M. A revoluble shaft Z is mounted upon the frame C and extends therethrough and has its axis in alignment with the axes of the pivots lllOlllltlDg the conductor bars upon the contacts (Z and (Z. t A. crank (Z mounted upon the shaft (Z adapted to be revolubly actuated thereby, is secured to the insulating connector (Z whereby rotatory motion of the shaft- (Z may be imparted to the bars (Z and (5 A spring {13 is coiled about the shaft cl and yieldingly retains the running arms of the bars in engagement with the running contacts al An arm (Z is mounted upon the crank (Z in substantial alignment With the connector at and extends toward the frame C.' A; radial lug (Z of a substantially triangular cross section is formed on the arm (Z7 and is adapted to engage a spring lat-eh F. A collar (Z is mounted upon the shaft, d and has a mutilated edge whereby A suita and o frame precludes longitudinal movement ofthe shaft (Z The spring latch F comprises a spring arm 7 mounted at one of its ends upon the frame C and having mounted upon its other end a catch f. The spring arm 7 and the catch f extend in substantial parallelism with the bracket a supporting the conductor bars. The end of the catch f adjacent the start inf); contacts (Z is developed into a knife edge having an angular face extending from the knife edge toward the frame C. Elie other end of the catch f or in other words the end of the latch disposed adjacent the running contacts al is developed into a substantial knife edge 7 having its angular face i disposed on the side of the latch opposite to the face f the face being substantially parallel with face 7. A notch or pocket is formed in the catch f in termcdiate its ends and upon that side of the catch adjacent the conductor bars. The

spring arm 7" is adapted to hold the catch 7 inthe patii the lug at. The lug (Z has a for- 'e d adapted to engage the face f" re shaft (Z is actuated to disei ge the running arms a 2111 unning conacts (1 and a rear knife edge 4Z adap V the face 7 *1 the catch f ween the c is actuated so as to separate the starting button contacts al and (Z The lug is also adapted to engage in the notch or pocket i formed upon the catch. The face (Z formed on the lug adjacent the knife edge (Z is adapted to engage the face on the latch as the lug moves by the catch and the face (Z formed on the lug intermediate the knife edges (Z and d thereon is adapted to engage the face on the catch as the d is moved toward the pocketf in the catch.

locking arm ll is i'nounted intermediate its ends upon a pivot G mounted upon the frame C. One end of the arm H is adapted to the collar cl mounted on the shaft (5, and the other end is adapted to he moved intermediate the collar a" mounted on the rod of and the frame G and to thereby preclude longitudinal movement of the rod a toward the frame C. wherefore it is impo sible to make an electrical contact between the spring contact arms a and the metallic hand al A spring -/a, normally retains the locking arms H in eugagn'icnt on the, collar (1 formed on the The face a collar (Z is disposed such a place that when the arms (Z of the conductor bars en gage the contacts 6Z said face d" will be esposed to the rod H and may be contacted by the rod I The control switch A described is adapted to control electrical communication between the wires 7;; and 5 or in other words I one pole switch.

In Fig. 5 is shown a double pole control switch. In this construction the metallic band is formed in two pieces a and a that are insulated from one another and each of which is adapted to make an electrical connection with one of the spring arms a, of which one is connected with the feed wire 6 and the other is connected with the return wire 6. In this construction the key a precludes relative rotary motion of the rod a and the metallic: band sections, wherefore the direction of the flow of current will not be modified by the control switch. It is also necessary in this construction to provide two conductor rods a and two flexible metallic connectors a.

A suitable line switch L is interposed between the source of electrical supply B and the control switch A.

The operation of my device is as follows:

\Ve will assume that the parts are in the relation shown in Fig. 1, the spring contact arms a being in the positions shown in full lines in Fig. 3. The handle a is then pulled away from the frame C to a position as shown in dotted lines in Fig. 3, thereby causing the spring contact arms (0 to engage the metallic band a and energizing the electro-magnet contained within the housing a, wherefore the armature a will be retained in such position by the magnetized core a, that the spring arms a will remain in contact with the metallic band a. The handle d is then revolved in such direction that the button contacts d are brought into engagement with the button contacts thereby completing a starting circuit embracing the resistances E and the motor M. The engagement of lug (Z in pocket f" precludes any other movement of the handle (Z After the motor armature has begun to revolve, the operator releases the handle (Z whereupon the spring (i moves the conductor bars about their pivotal mountings and cause the arms d thereon to engage the contacts (Z wherefore the motor is embraced in a full load circuit. As the spring (i moves the conductor bars about their pivotal mountings, the knife edge (Z and the face (Z on the lug (Z engage and pass over the face 7'" on the catch the spring arm f permitting movement of the catch f towards the conductor bar (1 When the running arms (Z engage the running contacts al the face (Z formed on the collar (1 is exposed to the arm H.

We will now assume that the line switch L is opened, wherefore the electro-magnet in the control switch is de-encrgized, and the action of the spring arms a causes the rod c to be moved longitudinally to such extent that the contact between the spring contact arms a and the metallic band a is broken. This movement of the rod (1 serves to move the collar 11 away from the frame C, whereupon the end of the arm H, whichwas being held in engagement with the collar (4 by means of the spring h, is separated from the collar (1 wherefore the spring it moves the arm H about its pivotal i'nounting G and causes the arm H to engage upon the face d formed on the collar d when the arm H is in this position the end thereof adjacent the control switch asumes a position intermediate the collar (4 and the frame C, wherefore it is impossible to move the rod c to such extent as to again move the spring contact arms 0. into engagement with the metallic band a":

From the foregoing it will be readily apparent that the only way in which it will be possible to again energize the motor will be by rerolubly aetua 1g the shaft (Z by means of the handle (Z and to thereby cause the arm H to be moved from the position it now assumes intermediate the collar a and the frame C. lVhen the handle d is moved in the proper direction for the pur pose stated, the knife edge d and the face 66 formed on the lug (Z engage and pass over the face f on the catch f, thereby moving the catch away from the conductor bar (5 When the lug al has been moved over the face f of the catch f against the yielding resistance of the spring arm 7, the catch is moved toward the bar d whereupon the handle (5 may be released and the lug (Z will engage in the pocket f in the catch, and the parts will again be in the position shown in Fig. 1.

lVhat I claim is:

1. In a device of the class described the combination of an operating switca comprising a starting contact, a running contact, a conductor bar adapted to assume positions in engagement with the contacts and a position spaced from the contacts, a control switch comprising normally disengaged contacts, one of which is electrically connected with the conductor bar, and the other of which is electrically connected with a source of electrical ener 'y, means adapted to move the contacts of the control switch into engagement with one another, and means to preclude movement of the contacts of the control switch from their normal positions by the c ntact moving means when the conductor bar is in engagemeI-it with the running contact.

In a device of the class described the combination of an operating switch com-- prising a starting contact, a running contact, a conductor bar adapted to assume positions in engagement with the contacts and a position spaced from the contacts, a control. switch comprising normally disengaged contacts, one of which is electrically connected with the conductor bar and the other of which is electrically connected with a source of electrical energy. means adapted to move the contacts of the control switch into engagement with one another, means to pre-. chide movement of the contact moving means when the conductor bar is in engagement with the running contact, and means adapted to render the locking means inoperative when the conductor bar is spaced from the starting and running contacts.

in a device of the class described the con'ibination o'i an operating switch comprising a starting contact, a running contact, a conductor bar adapted to assume positions enga ement with the contacts, and a poced from the contacts, a control ca con'iprising normally disengaged contacts, one of which is electrically connected with the conductor bar and the other of which is connected 't'h a source of electrical energy, a reciprocating rod adapted to more the contacts of the control switch into ie ement with one another, and a locking arr adapted to lock the reciprocating rod against movement from its no 'mal position when the conductor bar is in engagen'ient with the running contact.

4-. a deviceot the class described the combination of an. operating switch comprising a starting contact, a running contact, a coi'idnctor bar adapted to assume positions in eng genient with the contacts, and a position spaced from the contacts, a control switch comprising normally disengaged contacts, one of which is electrically connected with the conductor bar and the other off which is connected with a source of electrical energy, a reciprocating rod adapted to more the contacts of the control switch into engagen'ient with one another, a locking arm adapted to lock the reciprocating rod against movement from its normal position when the conductor bar is in engagement with the ru-i'ining contact, and means to release the reciprocating rod from the locking n when the conductor bar is spaced from the contacts.

5. In a deYice of the class described the combination of an operating switch comprising a starting contact, a running contact, a conductor bar adapted to assume positions in engagement with the contacts and a position spaced from the contacts, a control switch comprising normally disengaged contacts, one of which is electrically connected with the conductor bar and the other 01" which is connected with a source of electrical energy, means to move the contacts 01 the control switch into engagement with one another, means to retail the last mentioned contacts in engagement with one another, and means adapted to space the last mentioned contacts when released from the retaining means.

6. In a device of the class described the combination of an operating switch comprising a starting contact, a running contact, a conductor bar adapted to assume positions in engagen'ient with the contacts and a position spaced from the contacts, a control switch comprising normally disengaged con tacts, one of which is electrically connected with the conductor bar and the other of which is connected with a source of electri cal energy, means to move the contacts of the control switch into engagement with one another, means to retain the last mentioned contacts in engagement with one another, means adapted to space the last mentioned contacts when released from the retaining means, and means adapted to preelude movement of the control switch contacts into engagement with one another when the conductor bar is in engagement with the running contact.

7. In a device of the class described the combination oi an operating switch comprising a starting contact, arnnning contact, a conductor bar adapted to assume a position in engagement with the contacts and a position spaced from the contacts, a control switch comprising normally disenga ed contacts, one of which is electrically connected with the conductor bar and the other of which is connected to a source of electrical energy, means to move the contacts of the control switch into engagement with one another, means to retain the last mentioned contacts in engagement with one another, and means controlled from the operating switch for spacing the contacts of the control switch when the said contacts are released.

In testimony whereof, I have hereunto subscribed my name this 3 st day of May, 1921.

JOHN R. KELLEY. 

